Calendar availability: what is shared and what is not

With calendar sharing on (Integrations section), your Mac's agent shares your meeting time blocks for the next 48 hours so alerts can be calendar-aware. What leaves your Mac per meeting: start time, end time, and headcount. Nothing else, ever: no titles, no attendee names or emails, no locations, no notes.

“Meeting” has a strict definition:

• At least two attendees. A block you created for head-down work has no attendees and never counts.
• Not all-day and not multi-day; long background events are ignored.
• Not cancelled, and not something you declined.

The agent reads whatever calendars your Mac's Calendar app can see, including Google, iCloud, and Exchange, and sends updates only when your schedule actually changes. macOS asks for calendar permission the first time; you can revoke it in System Settings anytime.